The Grey Mansion is the story of Marie Arnette. She is the daughter of an Englishman and a French woman, who are very interested in her marrying and becoming a woman of society. Marie, however, is much more interested in the mysterious Grey Mansion, where there are strange parties are held for even stranger people. They arrive in their elegant costumes, but they never seem to leave. They simply disappear. Then Marie gets herself an invitation. Soon, she's intimately tied to the events of the mansion, the people who live there, and those who threaten it.